The West Branch City Council voted Monday to accept a bid of a bit more than $1 million for work on the new lift station and related improvements.

The low bid was 13.6 percent higher than the most recent engineer’s estimate of nearly $900,000.

According to Dave Schechinger of Veenstra & Kimm, the soil conditions at the site drove most of the increase, as contractors tried to price the risk of poor soil and water intrusion on the low-lying ground during construction.

The city received six bids that ranged as high as $1.3 million. The winning bid was submitted by Ricklefs Excavating, Ltd. of Anamosa.

Council Member Jim Oaks asked how a discussion of a $750,000 project over many months had resulted in a million-dollar bid.

Schechinger explained that Terracon’s soil borings and their report on site conditions led the contractors to protect themselves from uncertainty through the higher bids.

Schechinger also noted that a portion of the higher figures came from the city asking for a more-powerful pump.

Oaks questioned whether the city was overly cautious in building for a 500-year flood event.

Schechinger noted that the design actually falls between a 100- and a 500-year event, with the controls lifted above the 500-year lines.

The design is also meant to handle peak flow, so that there is no requirement for backup or bypass elements. He said this actually results in lower costs to the city.

Mayor Don Kesseler again stated his opposition to change orders, and asked Schechinger what he could foresee in potential cost increases before the project is completed.

After Council Member Colton Miller suggested a figure of 25 percent, Schechinger said that the bid package and contracts attempt to minimize the possibility of change orders. However, there is always a risk of change.

The council did not address whether this higher accepted bid would alter the planned bond financing for the project.